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EDGE INDEXING IN A GRID
FOR HIGHLY DYNAMIC VIRTUAL ENVIRONMENTS
by
Beomjoo Seo
A Dissertation Presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(COMPUTER SCIENCE)
May 2008
Copyright 2008 Beomjoo Seo

Newly emerging game-based application systems provide three-dimensional virtual environments where multiple users interact with each other in real--time. They are filled with autonomous, mutable virtual content which is continuously augmented by the users. To make the systems highly scalable and dynamically extensible, they are usually built on a client-server based grid subspace division where the virtual worlds are partitioned into manageable sub-worlds. In each sub-world, the user continuously receives relevant geometry updates of moving objects from remotely connected servers and renders them according to her viewpoint, rather than retrieving them from a local storage medium.; In such systems, the determination of the set of objects that are visible from a user's viewpoint is one of the primary factors that affect server throughput and scalability. Specifically, performing real--time visibility tests in extremely dynamic virtual environments is a very challenging task as millions of objects and sub-millions of active users are moving and interacting. We recognize that the described challenges are closely related to a spatial database problem, and hence we map the moving geometry objects in the virtual space to a set of multi-dimensional objects in a spatial database while modeling each avatar both as a spatial object and a moving query. Unfortunately, existing spatial indexing methods are unsuitable for this kind of new environments.; The main goal of this study is to present an efficient spatial index structure that minimizes unexpected object popping and supports highly scalable real--time visibility determination. We then uncover many useful properties of this structure and compare the index structure with various spatial indexing methods in terms of query quality, system throughput, and resource utilization. We expect our approach to lay the groundwork for next-generation virtual frameworks that may merge into existing web-based services in the near future.

EDGE INDEXING IN A GRID
FOR HIGHLY DYNAMIC VIRTUAL ENVIRONMENTS
by
Beomjoo Seo
A Dissertation Presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(COMPUTER SCIENCE)
May 2008
Copyright 2008 Beomjoo Seo